stereoman said:
I am extremely delightful with your - as usual - profi answers but actually can someone respond a bit more directly to the point or the gist ? I mean if you have a pair of loudspeakers without the sub and play through them ( but ONLY at 10 o'clock moderate volume level ) - without the subsonic filter - 5Hz to 30Hz and 18Khz to 25 Khz sound frequency ranges - does it strain the coils, woofers, tweeters etc in a long run ? Or are the speakers totally unaffected ? From what I read and understand is that you meant that it can be indeed detrimental or only when playing such extremes loud ?
The subsonic wild excursions of bass drivers can occur at even moderate listening levels if you are using vinyl. Back in the day, amps either had subsonic filters on their inputs, or were AC coupled and then the freqency response of the amp tailed off toward LF anyway. These days with amps having 'DC to daylight' performance, subsonic filters are a must for vinyl.
Along with its many other vices, this is a particular problem for vinyl because of RIAA equalisation. LF is attenuated when the disc is cut, and boosted when it is played back.
Unfortunately, this means any rumble and the effect of record warps are also boosted - by up to as much as 20dB. So a warped record can cause silent but wild excursions, which as pointed out above can cause the voicecoil to overextend with bad consequences for the speaker.